Problem: Luis ate 5 slices of pie. Omar ate 4 slices. If Luis ate $\dfrac{5}{11}$ of the pie, what fraction of the pie is remaining?
Solution: If 5 slices represent $\dfrac{5}{11}$ of the pie, there must have been a total of 11 slices. $\text{fraction of pie remaining} = \dfrac{\text{number of slices remaining}}{\text{number of slices total}}$ Together they ate 9 slices, which leaves 2 out of 11 slices remaining. There is $\dfrac{2}{11}$ of the pie remaining.